Myocardial fixation of anticardiac troponin I antibody and cardiac troponin I release.

BACKGROUND: The threefold aim of this experimental study was to test the correlation of cardiac troponin I released to myocardial infarction size and myocardial fixation of anticardiac troponin I antibody and to determine how long after myocardial infarction the measure of cardiac troponin I concentration can evaluate myocardial infarction size. METHODS: Forty rabbits were assigned either to a control group or to an experimental preconditioned group. Infarction was obtained by tightening a snare around the left anterior descending artery. Serial venous blood samples were drawn for measurement of cardiac troponin I. The rabbits were sacrificed at 72 hours and a histological study was performed to determine the infarct size and the size of the area void of fixation of anticardiac troponin I antibody. RESULTS: There was a linear correlation between the total amount of CTn I released and both infarct size (r=0.45, p<0.02) and the size of the area void of anti-cardiac troponin I antibody (r=0.47, p<0.02). These two sizes were strongly correlated (r=0.95, p<0.02). The hour 9 CTn I sample was the best correlated with both the infarct size (r=0.47, p<0.02) and the size of area void of anticardiac troponin I antibody (r=0.45, p<0.02). CONCLUSIONS: Our study shows that: 1) cardiac troponin I release is correlated to both myocardial infarction size and the size of area void of fixation of anticardiac troponin I antibody, 2) the area void of anticardiac troponin I antibody fixation includes the whole ischemic area, and 3) evaluation of myocardial infarction size can be obtained by CTn I concentration as early as the ninth hour.

Warm reperfusion and myocardial protection.

BACKGROUND: The aim of this study was to determine whether warm reperfusion improves myocardial protection with cardiac troponin I as the criteria for evaluating the adequacy of myocardial protection. METHODS: One hundred five patients undergoing first-time elective coronary bypass surgery were randomized to one of three cardioplegic strategies of either (1) cold crystalloid cardioplegia followed by warm reperfusion, (2) cold blood cardioplegia followed by warm reperfusion, or (3) cold blood cardioplegia with no reperfusion. RESULTS: The total amount of cardiac troponin I released tended to be higher in the cold blood cardioplegia with no reperfusion group (3.9+/-5.7 microg) than in the cold blood cardioplegia followed by warm reperfusion group (2.8+/-2.7 microg) or the cold crystalloid cardioplegia followed by warm reperfusion group (2.8+/-2.2 microg), but not significantly so. Cardiac troponin I concentration did not differ for any sample in any of the three groups. CONCLUSIONS: Our study showed that the addition of warm reperfusion to cold blood cardioplegia offers no advantage in a low-risk patient group.

Crystalloid versus cold blood cardioplegia and cardiac troponin I release.

BACKGROUND: Cardiac troponin I (CTnI) has been shown to be a marker of myocardial injury. The aim of this study was to compare antegrade crystalloid cardioplegia with antegrade cold blood cardioplegia with warm reperfusion using CTnI release as the criteria for evaluating the adequacy of myocardial protection. METHODS AND RESULTS: Seventy patients were randomly assigned to receive crystalloid or blood cardioplegia. CTnI concentrations were measured in serial venous blood samples drawn just before cardiopulmonary bypass and after aortic unclamping at 6, 9, 12, and 24 hours and daily thereafter for 5 days. ANOVA with repeated measures was performed to test the effect of the type of cardioplegia on CTnI release. The total amount of CTnI released was higher in the crystalloid cardioplegia group than in the blood cardioplegia group (11.2 +/- 8.9 versus 7.8 +/- 8.6 micrograms, P < .02). CTnI concentration was significantly higher in the crystalloid group than in the blood group in the samples drawn at hours 9 and 12. Three patients in each group had ECG evidence of perioperative myocardial infarction. Eight patients in the crystalloid group and five patients in the blood group had CTnI evidence of perioperative myocardial infarction. CTnI release was significantly lower in patients requiring no electrical defibrillation after aortic unclamping. CONCLUSIONS: Cold blood cardioplegia followed by warm reperfusion is beneficial in an unselected group of patients with a preserved left ventricular function undergoing an elective first coronary artery bypass grafting. CTnI allowed the diagnosis of small perioperative necrotic myocardial areas. The need for electrical defibrillation after aortic unclamping was related to a higher release of CTnI. A further study is necessary to determine whether this technique was beneficial because of cold blood cardioplegia, warm reperfusion, or both.

Effects of myocardial ischemia on the release of cardiac troponin I in isolated rat hearts.

BACKGROUND: The twofold aim of this experimental study was (1) to verify the correlation between the duration of ischemia and concentration of cardiac troponin I and (2) to compare the release of cardiac troponin I with histologic findings. METHODS: Experiments were done on 18 rat hearts, which were perfused according to the Langendorff method, immediately after excision in group I (control group) and after immersion for 3 hours (group II) and 6 hours (group III) in St. Thomas' Hospital solution at 4 degrees C. During reperfusion, the release of cardiac troponin I, creatine kinase isoenzyme MB, and lactate dehydrogenase, the recovery of left ventricular pressure, and heart rates were compared among the three groups. After the experiment, three samples of myocardium (left ventricle, right ventricle, and septum) were taken for histologic examination. RESULTS: Cardiac troponin I concentration was significantly higher in group III than in groups I and II and in group II compared with group I. Cardiac troponin I concentration increased as the ischemic period increased. The relation between cardiac troponin I release and ischemic duration tended to be linear. Creatine kinase MB and lactate dehydrogenase concentrations did not differ from one group to the other. Left ventricular pressure was not significantly different among the groups. In the control group, no heart had more than 10% of the myocytes affected. One of six hearts in group II and three of six in group III had more than 10% of myocytes affected. CONCLUSION: This experimental study showed (1) that cardiac troponin I is an early marker of ischemic injury and (2) that cardiac troponin I concentration increases as the ischemic period increases. Early cardiac troponin I release appears to correlate with the extent of ischemic injury in rats undergoing buffer perfusion.

Crystalloid cardioplegia route of delivery and cardiac troponin I release.

BACKGROUND: Cardiac troponin I (CTn I) has been shown to be a marker of myocardial injury. Incomplete distribution of cardioplegic solution may be responsible for injury in jeopardized myocardial areas. The aim of this study was to compare CTn I release with respect to the route of delivery of crystalloid cardioplegia, either antegrade only or initially antegrade followed by retrograde cardioplegia for the remainder of the operation, in patients undergoing elective coronary artery bypass grafting. METHODS: Sixty patients were randomly assigned to one of two cardioplegia groups. Cardiac troponin I concentrations were measured in serial venous blood samples drawn just before cardiopulmonary bypass and after aortic unclamping at 6, 9, 12, and 24 hours and daily thereafter for 5 days. Analysis of variance with repeated measures was performed to test the effect of route of delivery, coronary disease, collateral circulation, risk of cardioplegia maldistribution, and number of grafts on release of CTn I. RESULTS: Compared with the antegrade route, the combined route offered no advantage in an unselected group of patients undergoing an elective first cardiac operation and having preserved left ventricular function. The CTn I concentration did not differ between groups for any of the samples considered. In patients with major left main coronary artery stenosis, CTn I release was significantly higher at hour 9 in the antegrade group than in the group with combined delivery. CONCLUSIONS: A combined route of delivery of crystalloid cardioplegia is beneficial in patients with major stenosis of the left main coronary artery. Cardiac troponin I sensitivity is relevant in this study. Release of CTn I should be useful in determining the best form of myocardial protection for each patient.

Is surgery for aortic stenosis justified in patients over 75 years of age?

UNLABELLED: The upper age limit for cardiac surgery has constantly been extended since the 1980's, with the most pronounced extension observed in surgery of the calcified aortic stenosis (CAS). The aim of this study was to examine whether surgery is beneficial to the elderly population in terms of hospital mortality, long-term survival and quality of life. Between January 1989 and October 1992, 95 patients over 75 years of age underwent aortic valvular replacement (AVR) for CAS. There were 54 male and 41 female patients with a mean age of 79.7 +/- 2.8 years. All of them suffered from isolated or predominant CAS, associated with a coronary lesion requiring additional bypass procedures in 14 cases. Before surgery 67% of the patients were in NYHA class III and IV and 30% of them had suffered from acute pulmonary edema. Surgical priority was urgent in 10 patients. Mean aortic clamp time was of 55 minutes for the isolated CAS and 78 minutes for the bypass-associated CAS. A Carpentier-Edwards supra-annular bioprosthesis was implanted in 95.7% of the cases, associated with coronary bypass in 14 cases, with a mean of 1.6 bypasses per patient. Global hospital mortality was 11.5%. Emergency surgery was a predictive factor of in hospital mortality in multivariate analysis. Among the 84 survivors, 12 died secondarily, 4 of them due to cardiac causes during the follow-up period (26 +/- 4 months); similar to the mortality rate of the global population for the same age. The factors responsible for this late mortality in multivariate analysis were poor left ventricular status and diabetes mellitus. Survivor's quality of life is excellent with 78.6% of patients termed class I, autonomous and free of sequelae. IN CONCLUSION: despite an operative mortality rate much higher than in patients under 70, AVR for CAS is justified even in patients over 75 years as it offers a good quality of survival and a life expectancy identical to that of the general population of the same age.

Inter-observer reliability in the interpretation of coronary angiograms.

The interpretation of coronary angiograms is indispensable in determining procedure in coronary surgery. The aim of this study was to measure the overall reliability of a group of surgeons in the interpretation of coronary angiograms, surgical procedure and the evaluation of operative risk. Ten coronary angiograms were interpreted by eight cardiac surgeons at four different medical centers. Evaluation of coding discrepancies, in this case of multiple raters applying an ordinal-scale classification scheme (0, 1, 2) with no expert yardstick available for coding, was explored by a two-way random factor analysis of variance. Reliability was substantial for the assessment of stenosis irrespective of the artery (intraclass correlation coefficient (ICC) ranging from 0.92 to 1), and good for the distal part of the artery (ICC ranging from 0.83 to 0.86) as well as for the collateral provision (ICC ranging from 0.75 to 0.94). Agreement between surgeons was good with respect to the number of bypasses to be performed (ICC = 0.88). The number of bypass per patient varied from 2.6 to 3.2 depending on the surgeon. Agreement as to whether or not to bypass was substantial for the right coronary artery (ICC = 0.92), good for the marginal artery (ICC = 0.87) and fair for the left anterior descending artery (ICC = 0.60) and the circumflex artery (ICC = 0.60). There was a higher rate of agreement concerning inferior wall motion (ICC = 0.98) than of the anterior wall motion (ICC = 0.78). Agreement was substantial for ejection fraction (ICC = 0.93), operative risk (ICC = 0.93) and the type of coronary tree (ICC = 0.85). With respect to the overall set of items, no one surgeon disagreed significantly with the rest of the group. Some disagreement regarding anatomy suitable for revascularization exists between surgeons. Surgical assessment of risk is similar. Cardiac surgeons quickly learn to assess risk in a similar manner, even though they might not always graft the same anatomic vessels or assess regional wall motion similarly.

Prospective study of quality of life before and after open heart operations.

BACKGROUND: The aim of this prospective study, with completion of questionnaires before and 3 months after open heart operations, was to evaluate the improvement of quality of life brought about by these operations and the predictors of this improvement. METHODS: The Nottingham health profile questionnaire contains 38 subjective statements divided into six sections: energy, physical mobility, emotional reaction, pain, sleep, and social isolation. Factors influencing quality of life scores were determined by analysis of covariance. Factors influencing the status of the patients (improved or worsened) were determined by logistic regression. RESULTS: From January to July 1994, 215 consecutive patients underwent elective open heart operations. The comparison between mean preoperative and postoperative scores showed an improvement in all sections of quality of life. An average of 80% of patients were improved by their operations. Independent predictors of less improvement of quality of life scores were as follows: for the energy section, age over 70 and New York Heart Association functional class III or IV; for sleep, age over 70; for physical mobility, New York Heart Association functional class III or IV; for social isolation, female gender; and for pain, age over 70 and abnormal segmental wall motion. Independent predictors of patients worsened by operation were as follows: New York Heart Association functional class III or IV in the energy section (odds ratio = 3.7, 95% confidence interval 1.4 to 9.8) and in the physical mobility section (odds ratio = 2.4, 95% confidence interval 1.02 to 5.5), female gender in the social isolation section (odds ratio = 2.8, 95% confidence interval 1.03 to 7.7), and presence of at least one comorbid disease in the emotional reaction section (odds ratio = 2.5, 95% confidence interval 1.17 to 5.2). CONCLUSIONS: Cardiac operations improve quality of life in patients. The improvement is similar for patients undergoing coronary artery bypass grafting versus valve replacement, and for patients with no postoperative events versus those with nonlethal postoperative complications. The strongest predictive factors for quality of life are age and New York Heart Association functional class.

Quality of life after open-heart surgery in patients over 75 years old.

In a postal study we used the Nottingham Health Profile questionnaire to assess the quality of life of elderly survivors of open-heart surgery. From January 1984 to October 1993, 146 patients over 75 years of age underwent open-heart surgery in the Department of Cardiovascular Surgery at Beasançon (France). Eleven patients (7. 5%) died in the immediate post-operative course. Patients' mean follow-up was 3.4 +/- 2.4 years. Fourteen patients died during follow-up. One hundred and four completed Nottingham Health Profile questionnaires were returned. Five per cent of the patients lived in an old people's home. Six per cent of the patients were unable to walk at all. One patient out of five felt isolated. Fifteen per cent of the patients were in constant pain. Half of the patients took sleeping pills. Conversely, 87% of the patients felt an improvement after surgery. Sixty-two per cent continued to drive. Ninety-seven patients (92%) did at least one of the following three activities: watched television, listened to the radio, read books or magazines. Fifty-eight patients (56%) walked on a regular basis. The different types of pathology, of surgical procedures and whether or not a pacemaker was implanted during the post-operative course were not reflected in the quality of life (QOL) scores. After cardiac surgery, most of the patients were physically autonomous and related to their exterior world.

Myocardial revascularization using both attached internal thoracic arteries. Mid-term clinical evaluation of 117 cases.

The current trend in myocardial revascularization is to use arterial grafts in most, if not all cases. The right internal thoracic artery was a logical choice once the left internal thoracic artery patency on the LAD was known. This study presents our experience of using both attached internal thoracic arteries (ITA). Between January and October 1990, 159 myocardial revascularizations were performed in our department. In 117 cases, bilateral ITA grafting was used with non exclusion criteria. There were 100 male and 17 female patients, with a mean age of 61 +/- 8. The LITA was anastomosed to the LAD in 44 cases, and to the marginal artery in 74. The RITA was anastomosed to the LAD in 68 cases, to the marginal artery in 47 and to the right coronary artery in 2. An average of 3.5 bypasses per patient, including saphenous vein grafts, were performed. Six patients (5%) died within 30 days. Four patients (3.4%) were diagnosed as having periperative myocardial infarcts. There were no reoperations for bleeding. One patient (0.9%) presented a sternal wound infection. Mean follow-up was 18 +/- 7 months. Six patients died during the follow-up and the survival rate was 91%. Ninety-five patients (91%) were symptom-free, 9 patients had a recurrent angina. Postoperative coronary angiography was performed in 11 patients (10%).(ABSTRACT TRUNCATED AT 250 WORDS)

Use of cardiac troponin I as a marker of perioperative myocardial ischemia.

Troponin I is a contractile protein comprising three isoforms, two related to the skeletal muscle and one to the cardiac fibers. Cardiac troponin I (CTn I) is specific, without any cross-reactivity with the other two. Several studies have demonstrated its release after acute myocardial infarction. In contrast, CTn I never has been found in a healthy population, marathon runners, people with skeletal disease, or patients undergoing non-cardiac operations. Thus, CTn I is a more specific marker of cardiac damage than common serum enzymes. It is also more sensitive, allowing diagnosis of perioperative microinfarction and detection of acute myocardial infarction much earlier after the onset of ischemia (4 hours). Using a rapid one-step assay, we measured the release of CTn I in two groups of patients after operation: 20 with calcified aortic stenosis and normal coronary arteries (aortic valve replacement group and control group) and 20 undergoing coronary artery bypass grafting. In the overall population CTn I peaked at hour 6 and practically disappeared after day 5. Mean values were higher in the coronary artery bypass grafting group. In the aortic valve replacement group, a positive correlation was found between aortic cross-clamping time and CTn I, which is a reliable marker of cardiac ischemia during heart operations and can be used to evaluate cardioprotective procedures.

Aortic valve replacement in the elderly: a comparative assay of potential risk factor modification.

From January 1989 to October 1992, 208 consecutive patients underwent isolated aortic valve replacement for calcified aortic stenosis in our department. Since the mean age of this patient population was 70 +/- 9 years, a retrospective clinical study was completed to assess the potential influence of advanced age on the independent predictors of early and late mortality. Hospital mortality was 6.2% (13 patients). Total follow up was 422.5 patient-years with a mean of 26 months. Nineteen patients died during the follow up period, equivalent to 4.5% per patient-year late mortality rate. Survival including hospital death was 88 +/- 2%, 86 +/- 2% and 79 +/- 4% at one, two and three years respectively. Eighteen variables as potential predictors of early and late mortality were studied. Predictors of hospital mortality were determined by logistic regression analysis, and those of late mortality by Cox proportional hazard model. Results were expressed as odds ratio (OR) or relative risk (RR). Age greater than 70 years (OR = 9.8, 95% CI = 1.2 to 80) and emergency surgery (OR = 8, 95% CI = 2.1 to 31) appeared as independent predictors of hospital mortality in multivariate analysis. Age above 75 years (RR = 3, 95% CI = 1.1 to 8.3), preoperative acute pulmonary edema (RR = 2.9, 95% CI = 1.1 to 7.7) and emergency surgery (RR = 4.2, 95% CI = 1.2 to 15) were independently associated with decreased late survival. Advanced functional class (NYHA III-IV) was shown to be an independent predictor of early or late mortality only in univariate analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

[The treatment of acute dissections of the aorta by circulatory arrest under deep hypothermia and retrograde cerebral perfusion]. / Le traitement des dissections aiguës de l'aorte en arrêt circulatoire sous hypothermie profonde et rétroperfusion cérébrale.

The use of profound hypothermia with retrograde cerebral perfusion was described by Ueda in 1988. The innovation of this technique was the retrograde perfusion of oxygenated blood at a temperature of 15 degrees C and a pressure of 25 mmHg via the superior vena cava during the circulatory arrest period. Between february 1993 and march 1994, this technique was used in 12 patients in our department, with acute dissection of the aorta present in 8 cases. In this series of 8 patients, 3 females and 5 males aged 47 to 73 (mean age 60 years)--there were 7 type I acute dissections, one of which occurred on an annulo-aortic ectasia, and 1 type III retrograde dissection with hemopericardium. Treatment consisted of 7 supracoronary tubes one of which extended as a tongue along the inner curvature of the aortic arch, and 1 Cabrol's procedure. Mean times were: extracorporeal circulation: 148 +/- 50 minutes, core cooling: 60 +/- 20 min., circulatory arrest: 34 +/- 9 min., core rewarming: 69 +/- 27 min. Average flow of retrograde perfusion was 440 +/- 350 ml/minute. Mean post operative bleeding was 650 +/- 150 ml for the first 48 hours. No patient awoke with signs of neurological deficiency. Seven patients were weaned from mechanical ventilation either on day 1 or day 2. They presented normal neurological examination. One patient in whom minor post operative disturbance postponed mechanical ventilation weaning to day 4, was neurologically intact upon examination prior to hospital discharge. One patient with no initial post operative complication, died of thrombosis of the Cabrol prosthesis at day 8.(ABSTRACT TRUNCATED AT 250 WORDS)

[Cerebral protection by retrograde perfusion in the treatment of acute aortic dissection]. / Protection cérébrale par rétroperfusion dans le traitement des dissections aiguës de l'aorte.

Four consecutive patients underwent resection and graft replacement of ascending aorta or aortic arch for acute dissection. Retrograde cerebral perfusion (RCP) was used during circulatory arrest. RCP at 15 degrees C was administered through the superior vena cava. Duration of cerebral ischaemia and cardiopulmonary bypass averaged 33 and 156 minutes respectively. Retrograde perfusion flow was regulated from 100 to 800 ml/minute to maintain an internal jugular vein pressure of about 25 cm H2O. All patients survived. Three patients awoke neurologically intact. Minor neurological disturbance was found in 1 patient, he was discharged from hospital at day 11 without any detectable neurological deficit. This technique was attractive because it provided a dry operative field unencumbered by perfusion cannulas or clamps, facilitated construction of a more secure distal anastomosis, and avoided the risk of further injury resulting from the aortic cross clamp. It seems that RCP allows longer circulatory arrest time.

The Y graft: myocardial revascularization with both internal thoracic arteries. Evaluation of eighty cases with coronary angiographic assessment.

The use of bilateral in situ internal thoracic arteries is restricted by the risk of sternal devascularization, the length of the pedicle, and the necessity to avoid crossing the midline. The aim of this study is to evaluate Y grafts achieved by anastomosing the proximal end of the free right internal thoracic artery to the side of the attached left internal thoracic artery. Y grafts were performed in 80 patients, aged 41 to 74 years (mean age 58.6 years) between May 1991 and September 1992. Two different techniques were used. Thirty-four patients were included in group 1 and 46 in group 2. Seventy-nine grafts were performed from the left internal thoracic artery to the left anterior descending artery. The right internal thoracic artery was anastomosed to the diagonal artery (5 times), the marginal branch (67 times), the circumflex artery (7 times) and the right coronary artery (2 times). Seventy-five complementary saphenous vein bypasses were performed in 58 patients. Operative mortality was 2.5%. Two patients had perioperative myocardial infarcts (2.5%) on nonbypassed sites. Three patients had sternal wound infections (3.7%). Sixty-two patients (80%) were reexamined by angiography at month 6-25 in group 1 and 37 in group 2. Sixty left internal thoracic artery bypass grafts (97%) were patent versus 39 right internal thoracic artery bypass grafts (63%). In group 1, 23 of 25 left internal thoracic artery bypass grafts were patient (92%) versus 12 right internal thoracic artery grafts (48%). In group 2, all 37 left internal thoracic artery bypass grafts were patent (100%) versus 27 right internal thoracic artery grafts (73%). With this procedure, particular attention must be paid to the length of the right internal thoracic artery, and extensive training is required.